Seal assemblies are well known for providing a dynamic fluid seal between a housing having a bore and a shaft having an outer running surface protruding through the bore and rotating relative to the housing. Such seal assemblies typically comprise a rigid carrier for supporting the seal assembly in the bore. A mounting collar formed from rubber is often molded about the rigid carrier to provide a press-fit connection between the seal assembly and the housing thereby aligning the seal assembly within the bore about the outer running surface. The rigid carrier supports a sealing element, e.g., a lip seal, encircling and dynamically sealing the outer running surface of the shaft.
The sealing element, e.g., the lip seal, is often formed from polytetrafluoroethylene (PTFE) because PTFE offers superior thermal and chemical resistance and a low coefficient of friction. However, PTFE has comparatively low wear and abrasion resistance and is costly, limiting its use to only certain sealing applications or requiring extra measures to protect the PTFE from damage from the environment.
It is an object of the present invention to provide a seal assembly which overcomes or minimizes the drawbacks to typical PTFE seals, while preserving their advantages.